Characterization and Optimization of Chrome Free Tanning System Using Combination of Chestnut and Tetrakis Hydroxymethyl Phosphonium Sulfate

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Addis Ababa University


Currently, chrome tanning accounts for more than 90% of global leather manufacturing. This tanning system result in significant material loss and considerable environmental concerns. In the present work, chrome free combination tanning system using a combination tanning system based on Chestnut and THPS is presented. The processing method for Experimental tanning trials were carried out with different percentages of Chestnut as a tannage followed by varying percentages of THPS as a re-tannage for process optimization. The leathers obtained were characterized for their physical strength characteristics, comfort & organoleptic properties, scanning electron microscopic analysis, reflectance measurements and environmental characteristics. The Chestnut-THPS leathers tanned using 20% chestnut followed by 2% THPS resulted in shrinkage temperature of 95OC. The hydrothermal stability of the combination has been found better than the Chestnut alone and THPS alone tanned leathers, respectively. The strength properties and comfort properties of leathers obtained are on par with or better than the control chrome, Chestnut alone and THPS alone tanned leathers. The organoleptic properties of the experimental crust leathers exhibit good grain smoothness, fullness, grain tightness, general appearance compared to control chrome tanned crust leathers. Environmental impact assessment shows the combination tanning system results a significant reduction in TS, TDS, TSS and BOD in the waste water when compared to that of control tanning system. The study presented in this paper established the use of Chestnut and THPS combination tanning system as an effective alternative cleaner tanning methodology.



Combination tanning, Chestnut, THPS, Chromium sulfate, Upper leather, Shrinkage temperature